Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a first image in a sequence of a first embodiment of the display screen or portion thereof with transitional graphical user interface according to the claimed design;

FIG. 2 is a front view of a second image in a sequence of the first embodiment according to the claimed design;

FIG. 3 is a front view of a third image in a sequence of the first embodiment according to the claimed design;

FIG. 4 is a front view of a first image in a sequence of a second embodiment according to the claimed design; and,

FIG. 5 is a front view of a second image in a sequence of the second embodiment according to the claimed design.

The greyscale field shown in FIGS. 1, 2, and 4 and the gradient background shown in FIGS. 1-5 of the graphical user interface are claimed subject matter.

The longer length broken line showing of a display screen and the intermediate length broken line showing of a display screen boundary, are included for the purpose of illustrating environmental structure. The remaining broken lines represent elements of the graphical user interface that are excluded from the claim.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1-3 and FIGS. 4-5. The process or period in which one image transitions to another forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 